package pers.zb.common.util.util;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.apache.commons.beanutils.PropertyUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.Assert;

/**
 * 反射的Util函数集合.
 * 
 * 提供访问私有变量,获取泛型类型Class,提取集合中元素的属性,转换字符串到对象等Util函数.
 * 
 */
public class ReflectionUtils {

    private static Logger logger = LoggerFactory
            .getLogger(ReflectionUtils.class);

    /**
     * 直接读取对象属性值, 无视private/protected修饰符, 不经过getter函数.
     */
    public static Object getFieldValue(final Object object,
            final String fieldName) {
        Field field = getDeclaredField(object, fieldName);

        if (field == null)
            throw new IllegalArgumentException("Could not find field ["
                    + fieldName + "] on target [" + object + "]");

        makeAccessible(field);

        Object result = null;
        try {
            result = field.get(object);
        } catch (IllegalAccessException e) {
            logger.error("不可能抛出的异常{}", e.getMessage());
        }
        return result;
    }

    /**
     * 直接设置对象属性值, 无视private/protected修饰符, 不经过setter函数.
     */
    public static void setFieldValue(final Object object,
            final String fieldName, final Object value) {
        Field field = getDeclaredField(object, fieldName);

        if (field == null)
            throw new IllegalArgumentException("Could not find field ["
                    + fieldName + "] on target [" + object + "]");

        makeAccessible(field);

        try {
            field.set(object, value);
        } catch (IllegalAccessException e) {
            logger.error("不可能抛出的异常:{}", e.getMessage());
        }
    }

    /**
     * 直接调用对象方法, 无视private/protected修饰符.
     */
    public static Object invokeMethod(final Object object,
            final String methodName, final Class<?>[] parameterTypes,
            final Object[] parameters) {
        Method method = getDeclaredMethod(object, methodName, parameterTypes);
        if (method == null)
            throw new IllegalArgumentException("Could not find method ["
                    + methodName + "] on target [" + object + "]");

        method.setAccessible(true);

        try {
            return method.invoke(object, parameters);
        } catch (Exception e) {
            throw convertReflectionExceptionToUnchecked(e);
        }
    }

    /**
     * 循环向上转型, 获取对象的DeclaredField.
     * 
     * 如向上转型到Object仍无法找到, 返回null.
     */
    protected static Field getDeclaredField(final Object object,
            final String fieldName) {
        Assert.notNull(object, "object不能为空");
        Assert.hasText(fieldName, "fieldName");
        for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass
                .getSuperclass()) {
            try {
                return superClass.getDeclaredField(fieldName);
            } catch (NoSuchFieldException e) {
                // Field不在当前类定义,继续向上转型
            }
        }
        return null;
    }

    /**
     * 强行设置Field可访问.
     */
    protected static void makeAccessible(final Field field) {
        if (!Modifier.isPublic(field.getModifiers())
                || !Modifier.isPublic(field.getDeclaringClass().getModifiers())) {
            field.setAccessible(true);
        }
    }

    /**
     * 循环向上转型,获取对象的DeclaredMethod.
     * 
     * 如向上转型到Object仍无法找到, 返回null.
     */
    protected static Method getDeclaredMethod(Object object, String methodName,
            Class<?>[] parameterTypes) {
        Assert.notNull(object, "object不能为空");

        for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass
                .getSuperclass()) {
            try {
                return superClass.getDeclaredMethod(methodName, parameterTypes);
            } catch (NoSuchMethodException e) {
                // Method不在当前类定义,继续向上转型
            }
        }
        return null;
    }

    /**
     * 通过反射,获得Class定义中声明的父类的泛型参数的类型. 如无法找到, 返回Object.class. eg. public UserDao
     * extends HibernateDao<User>
     *
     * @param clazz
     *            The class to introspect
     * @return the first generic declaration, or Object.class if cannot be
     *         determined
     */
    @SuppressWarnings("unchecked")
    public static <T> Class<T> getSuperClassGenricType(final Class clazz) {
        return getSuperClassGenricType(clazz, 0);
    }

    /**
     * 通过反射,获得定义Class时声明的父类的泛型参数的类型. 如无法找到, 返回Object.class.
     * 
     * 如public UserDao extends HibernateDao<User,Long>
     *
     * @param clazz
     *            clazz The class to introspect
     * @param index
     *            the Index of the generic ddeclaration,start from 0.
     * @return the index generic declaration, or Object.class if cannot be
     *         determined
     */
    @SuppressWarnings("unchecked")
    public static Class getSuperClassGenricType(final Class clazz,
            final int index) {

        Type genType = clazz.getGenericSuperclass();

        if (!(genType instanceof ParameterizedType)) {
            logger.warn(clazz.getSimpleName()
                    + "'s superclass not ParameterizedType");
            return Object.class;
        }

        Type[] params = ((ParameterizedType) genType).getActualTypeArguments();

        if (index >= params.length || index < 0) {
            logger.warn("Index: " + index + ", Size of "
                    + clazz.getSimpleName() + "'s Parameterized Type: "
                    + params.length);
            return Object.class;
        }
        if (!(params[index] instanceof Class)) {
            logger.warn(clazz.getSimpleName()
                    + " not set the actual class on superclass generic parameter");
            return Object.class;
        }

        return (Class) params[index];
    }

    public static Class getInterfaceClassGenricType(final Class clazz,
            final int index) {

        Type[] genTypes = clazz.getGenericInterfaces();
        if (genTypes == null || genTypes.length == 0) {
            logger.warn(clazz.getSimpleName() + "'s not impl interface ");
            return Object.class;
        }

        if (!(genTypes[0] instanceof ParameterizedType)) {
            logger.warn(clazz.getSimpleName()
                    + "'s superclass not ParameterizedType");
            return Object.class;
        }

        Type[] params = ((ParameterizedType) genTypes[0])
                .getActualTypeArguments();

        if (index >= params.length || index < 0) {
            logger.warn("Index: " + index + ", Size of "
                    + clazz.getSimpleName() + "'s Parameterized Type: "
                    + params.length);
            return Object.class;
        }
        if (!(params[index] instanceof Class)) {
            logger.warn(clazz.getSimpleName()
                    + " not set the actual class on superclass generic parameter");
            return Object.class;
        }

        return (Class) params[index];
    }

    /**
     * 提取集合中的对象的属性(通过getter函数), 组合成List.
     * 
     * @param collection
     *            来源集合.
     * @param propertyName
     *            要提取的属性名.
     */
    @SuppressWarnings("unchecked")
    public static List convertElementPropertyToList(
            final Collection collection, final String propertyName) {
        List list = new ArrayList();

        try {
            for (Object obj : collection) {
                list.add(PropertyUtils.getProperty(obj, propertyName));
            }
        } catch (Exception e) {
            throw convertReflectionExceptionToUnchecked(e);
        }

        return list;
    }

    /**
     * 提取集合中的对象的属性(通过getter函数), 组合成由分割符分隔的字符串.
     * 
     * @param collection
     *            来源集合.
     * @param propertyName
     *            要提取的属性名.
     * @param separator
     *            分隔符.
     */
    // @SuppressWarnings("unchecked")
    // public static String convertElementPropertyToString(final Collection
    // collection, final String propertyName,
    // final String separator) {
    // List list = convertElementPropertyToList(collection, propertyName);
    // return StringUtils.join(list, separator);
    // }

    /**
     * 转换字符串类型到clazz的property类型的值.
     * 
     * @param value
     *            待转换的字符串
     * @param clazz
     *            提供类型信息的Class
     * @param propertyName
     *            提供类型信息的Class的属性.
     */
    // public static Object convertValue(Object value, Class<?> toType) {
    // try {
    // DateConverter dc = new DateConverter();
    // dc.setUseLocaleFormat(true);
    // dc.setPatterns(new String[] { "yyyy-MM-dd", "yyyy-MM-dd HH:mm:ss" });
    // ConvertUtils.register(dc, Date.class);
    // return ConvertUtils.convert(value, toType);
    // } catch (Exception e) {
    // throw convertReflectionExceptionToUnchecked(e);
    // }
    // }

    /**
     * 将反射时的checked exception转换为unchecked exception.
     */
    public static RuntimeException convertReflectionExceptionToUnchecked(
            Exception e) {
        if (e instanceof IllegalAccessException
                || e instanceof IllegalArgumentException
                || e instanceof NoSuchMethodException)
            return new IllegalArgumentException("Reflection Exception.", e);
        else if (e instanceof InvocationTargetException)
            return new RuntimeException("Reflection Exception.",
                    ((InvocationTargetException) e).getTargetException());
        else if (e instanceof RuntimeException) {
            return (RuntimeException) e;
        }
        return new RuntimeException("Unexpected Checked Exception.", e);
    }
}
